Messages in this thread | | | From | Guenter Roeck <> | Date | Thu, 7 Apr 2022 09:28:41 -0700 | Subject | Re: [PATCH] platform/chrome: cros_ec_typec: Check for EC driver |
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On Wed, Apr 6, 2022 at 6:16 PM Akihiko Odaki <akihiko.odaki@gmail.com> wrote: [ ... ] > >>> ec_dev = dev_get_drvdata(&typec->ec->ec->dev);
I completely missed the part that this is not on the parent.
> >>> + if (!ec_dev) > >>> + return -EPROBE_DEFER; [ ... ] > > 1. The parent exists and dev_get_drvdata(pdev->dev.parent) returns > non-NULL value. However, dev_get_drvdata(&typec->ec->ec->dev) returns > NULL. (Yes, that is confusing.) I'm wondering
I am actually surprised that typec->ec->ec is not NULL. Underlying problem (or, one underlying problem) is that it is set in cros_ec_register():
/* Register a platform device for the main EC instance */ ec_dev->ec = platform_device_register_data(ec_dev->dev, "cros-ec-dev", PLATFORM_DEVID_AUTO, &ec_p, sizeof(struct cros_ec_platform));
"cros-ec-dev" is the mfd device which instantiates the character device. On devicetree (arm64) systems, the typec device is registered as child of google,cros-ec-spi and thus should be instantiated only after the spi device has been instantiated. The same should happen on ACPI systems, but I don't know if that is really correct.
I don't know what exactly is happening, but apparently typec registration happens in parallel with cros-ec-dev registration, which is delayed because the character device is not loaded. As mentioned, I don't understand why typec->ec->ec is not NULL. Can you check what it points to ?
Thanks, Guenter
> dev_get_drvdata(pdev->dev.parent) returned NULL in the following crash > log but it would be a problem distinct from what is handled with my patch: > https://lore.kernel.org/lkml/CABXOdTe9u_DW=NZM1-J120Gu1gibDy8SsgHP3bJwwLsE_iuLAQ@mail.gmail.com/ > > 2. My patch returns -EPROBE_DEFER instead of -ENODEV and I confirmed it > will eventually be instantiated. > > Regards, > Akihiko Odaki > > > > > Guenter > > > >> Thanks, > >> > >> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/platform/chrome?id=ffebd90532728086007038986900426544e3df4e >
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